Magnetic Field Computation for PMTs Shielding Optimization

International audienceThe Photon Array for the studies of Radioactive and Ion Stable beams (PARIS) is a multidetector of clusters. Each cluster is composed of 9 units of two-shells phoswiches of LaBr3/NaI scintillators optically coupled to one photomultiplier tube. PARIS will be used in combination with the VAMOS spectrometer at GANIL. During the experiment, PMTs will be exposed to the constant magnetic fringe fields produced by a quadrupole. Magnetic shielding is essential to efficiently lower the magnetic field inside the PMTs. The design and the optimization of this shield is presented. A comparison is done between the simulated and the experimental values